Livestock Research for Rural Development 26 (7) 2014 Guide for preparation of papers LRRD Newsletter

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Evaluation of Tanzanian local chicken reared under intensive and semi-intensive systems: I. Growth performance and carcass characteristics

Y D Sanka and S H Mbaga1

Ministry of Livestock and Fisheries Development, P.O. Box 9152, Dar es Salaam, Tanzania
1Department of Animal Science and Production, P.O. Box 3004, Sokoine University of Agriculture, Morogoro Tanzania


The objective of this study was to determine the effect of rearing systems, sex and age at slaughter on growth performance and carcass traits of local chicken. A total of 96 local weaned chicks (two months old) were bought from farmers in Morogoro peri-urban and reared under two different rearing system viz. intensive and semi-intensive systems.  The birds were initially weighed and randomly assigned to each rearing system with equal number of males and females (48 birds per system). Two pens with deep litter were used to house the birds. Spacing for birds in both systems was 4birds/m2.  However, birds under semi-intensive system had free access to grassy paddock (1 bird/10m2). All birds were offered the same diet with semi-intensive group receiving half of what was offered to the intensive group. Random sample of 24 males and 24 females in each rearing system were slaughtered at five and seven month.


Body weights at slaughter and body weight gain of birds from semi-intensive system were significantly lower than of those kept in intensive system. There was no difference in dressing percentage between the two rearing systems, the values being 65.2% and 65.7% for intensive and semi-intensive respectively. Dressing percent was higher (67.7%) at seven month than at five month of age (63.2%). The rearing systems significantly affected the breast percentage, being higher in semi-intensive (25.1%) compared to intensive system (23.3%).  Thigh percent was not influenced by rearing system or slaughter age, while drum stick percent was significantly lower at seven month old bird compared to five month old birds.  From the study, it is concluded that local chicken with modest supplementation and assuming availability of scavenging feed resources, semi-confinement system of chicken rearing could be more appropriate for the small holder poultry keepers. 

Keywords: age at slaughter, foraging, rearing system, scavenging, SFB


Poultry, particularly chickens are the most widely kept and most numerous livestock species in the world (Perry et al 2002; Moreki et al 2010). Local chickens are widely distributed in rural and peri-urban areas where they play the important role of income generation, food production and social aspect (Mwalusanya et al 2001; Thornton et al 2002; Moreki et al 2010). In Tanzania, local chickens makeup over 70% of the total chicken population and supply most of the poultry meat and eggs for domestic market (MLFD 2012). Local chickens are reared under different production systems, mainly scavenging, semi-intensive system and to a lesser extent intensive systems. Free range system is dominant in most rural areas and has been practiced for many years in Africa (Sonaiya 1990 and Kitalyi 1998). Although requiring minimal resource input and considered secondary to other agricultural activities by farmers, this type of production has many limitations including diseases, predators and poor growth rate (Mwalusanya et al 2001; Mutayoba et al 2012). Furthermore, scavenging and semi-scavenging are characterized by low plane of nutrition that varies with season (Mwalusanya et al 2002; Goromela et al 2006) ultimately affecting the growth performance.


Presently, most research attempts on local chicken have been focused on increased production, disease management and marketing (Msofe et al 2002; Mwalusanya et al 2002; and Mlozi et al 2003).   However, there is an increase in demand of local chicken meat and eggs in Africa owing to their good taste compared to products from exotic commercial strains. In this regard, the increased demand, need to be matched with quality which to a larger extent will depend on the management systems to be adopted.  This study therefore investigates the effects of rearing systems and age at slaughter on growth performance and gross carcass characteristics.

Materials and Methods

Study area


The research was conducted at the Sokoine University of Agriculture, Department of Animal Science and Production poultry unit. The area is situated 6o S and 37o E and it is about 3 km south of Morogoro town. The area lies on the foot of the slopes of Uluguru Mountain at an elevation of about 500-600m above sea level. The annual rainfall ranges between 600 and 1000 mm per annum and the temperature ranges between 30 oC and 35 oC during the hottest months (October to January) and 20 – 27 oC in the coolest months (April to August).


Experimental design and bird management


A flock of 96 local chickens at two months of age was used with 48 males and 48 female. Two rearing systems were evaluated viz. intensive (full confinement) and semi-intensive (partial confinement). A completely randomized experimental design was applied and males and females were allocated equally in the two rearing systems. Initially the groups were arranged such that the mean body weight in each group was about 519 g. The birds under intensive system were raised on deep litter with a density of 4birds/m2 in each pen. Temperature was 25±3°C and a relative humidity was 65-75% on average. All birds were group fed with a diet containing 19% CP and 2679KJ ME from 2nd month to 5th and or 7th month of slaughter. On average 86 grams of feed was offered per day to each bird under intensive system.


Birds under semi-intensive system were put in a separate pen (4 birds/m2), but with a free access to open grassy area (1 bird/10m2). They were fed half of the amount allocated to birds under intensive system. Feed and water were provided outdoors using trough feeders and drinkers. Ground predators were excluded by iron sheet fencing. For security reason semi-intensive birds were confined to indoor pens at night.


Data collection


All birds were weighed initially and thereafter, once per month. One half of the birds (n=48) with equal number of males (n=24) and females (n=24) in each rearing system were slaughtered for carcass evaluation at day 150 (approx. 5 month) and the remaining half slaughtered at day 210 (approx. 7 month). The birds were fasted for 12 hours, weighed individually and slaughtered by manual exsanguinations.  The carcass was eviscerated and the warm carcass weighed. This was followed by removal and weighing of carcass parts mainly; the breast, thigh and drumstick. The dressing percent was expressed as percent of eviscerated carcass to the live body weight after fasting. The breast, thigh and drumstick weights were expressed as percent of dressed carcass weight.


Data analyses


Data were subjected to analysis of variance using a General Linear Model (GLM) procedure in SAS Software System (SAS 2006). Means were compared using t-test. The following statistical model was used to analyze the effects of rearing system sex and slaughter age on production and carcass parameters. Interaction were tested but were not significantly different.

Yijk = μ + Ri + Sj + Ak + b(x-∑𝑥𝑛)ijk + eijk


Yijk       = an observation for a given variables.

μ          = overall mean

Ri           = effect of the ith rearing system (i: 1=semi-intensive, 2=intensive)

Sj         = effect of the jth sex (j: 1=male, 2=female)

Ak          = age at slaughter (k: 1=five month, 2=seven months)

b(x-∑𝑥𝑛)ijk = initial weight as covariate

x          = initial weight of chicken

𝑥𝑛    = average initial weight

b          = regression coefficient

eijk        = residual random error

Results and Discussion

Growth Performance


Figure 1 show that the body weight of chicken reared under intensive system had greater response in body weight beginning week three than those under semi-intensive system. However, at week seven the difference was rather small; the group under intensive system appearing to slow down which could have resulted from inadequate feed intake. The continued growth under semi-intensive system could probably be associated with compensatory effects.

Figure 1: Effect of rearing system and age on live body weight.

On overall, the weight gain of chickens in the semi-intensive system was significantly (P<0.05) lower (9.84 g/d) than in the intensive system (11.95 g/d), the difference being about 21% (Table 1). The higher weight of birds kept in full confinement could be explained by higher feed intake, and probably better feed conversion efficiency due to lower energy expenditure for exercise. However, birds under semi-intensive system were more efficient in feed conversion ratio. Birds under partial confinement (semi-intensive) gained less despite the access to range, which provided enough green but, with limitation of energy. It should be noted that birds under semi-intensive system were given only half of the feed that were given to full confined group. These results are similar to those reported by Mutayoba et al (2012); Magala et al (2012); Dou et al (2009) and Castellini et al (2002) who reported growth rate and feed efficiency in scavenging, free-range and outdoor organic rearing respectively to be lower than in intensive rearing system.   The ADG ranged from 10.4 to 15.2 g/day in males and 8.4 g/day to 11.6 g/day in females. These results are closer to the average value of 10.81 g/d reported by Raach-Moujahed et al (2011) in  Tunisian local chicken, but higher than the value of 6.6 – 8.0g reported by Hassen et al (2006) in Ethiopia. The differences observed in these studies could be attributed to difference in genetic background of the stock used as well as type of management, including feeds.


As expected, body weight at slaughter increased progressively with age and at seven months old, both males and females were heavier compared to five month old birds (Table 1). Comparison between slaughter ages indicates that under intensive system, the difference in cumulative weight between males and females were about 4% (428.9 g for males and 446.8 g for females). This difference was much higher (10%) under semi-intensive system in favour of males (545.7g for males and 492.2 g for females).   


In this study there was a distinct difference in magnitude of decline in growth rate by sex and rearing system. Males under intensive system lost about 4 g between month five and month seven compared to males under semi-confinement (-1.5g). These observations connotes that males under semi-intensive had less stress compared to those under intensive system by having space to escape in case of presence of aggressive males. This probably gave them more access to feed and also explain the higher cumulative weight gain of males under semi-confinement.


The trend in body weight shows that under both systems, birds could be slaughtered at the age of five month and above when birds have attained body weight of more than one kilogram.  This implies that if scavenging feed resources are adequate, semi-confinement system of rearing with modest supplementation could thus be more economical for the small holder poultry keepers. Kitalyi (1998) support the contention that free-ranging chicken should be given supplementary feeds depending on seasonal availability of common feed resources. When such feeds are adequate performance of such birds can be improved and the feed costs will always be lower than if birds are fully confined. However, if birds are left to roam freely, the distance moved by the birds in search of feed can have negative effects on growth and ultimately affect slaughter age and meat quality. Nonetheless, body weights at five month old in this experiment are within the range of weights reported for some of the Tanzania ecotypes. For example, Lwelamira et al (2008b) reported body weights of 1295-2318 g for Kuchi ecotype and 1070-2040 g for Medium ecotype under intensive system and 870-1567 g for Kuchi ecotype and 817-1419 g for Medium ecotype under extensive system at the age of 20 weeks.  Comparable results were also reported in growth parameters by Hassan et al (2006) in indigenous chickens under intensive management conditions in Northwest Ethiopia.


Table 1. Mean values for growth and feed conversion ratio of local chicken reared under intensive and semi-intensive systems


Rearing system










Slaughter weight (g)









ADG (g/day)


















ADG = Average daily weight gain, FCR = Feed conversion ratio, SEM = Standard error of mean.


Carcass traits


The effects of rearing system, sex and age on carcass traits are shown in table 2 and figure 2. There was no significant difference between dressing percent in the two rearing systems, the value being 65.2% and 65.7% for birds under intensive and semi-intensive system respectively.  The results conform to those reported by Dou et al (2009), Cheng et al (2008), Fanatico et al (2005) and Raach-Moujahed and Haddad (2013). Raach-Moujahed and Haddad (2013) reported a mean dressing percent of 68.6 percent for Tunisia local chicken raised for 112 days with outdoor access.  Likewise, there was no significant difference in dressing percent between males and females within slaughter age, the average values being 66.2 and 64.7 percent for males and females respectively. However, birds slaughtered at seven month had significantly higher carcass percent (67.7) than those at five month (63.2%) (Figure 2). The higher dressing percent in 7 month birds is expected since, as birds increase in weight there is proportionate increase in muscle and other tissues except bones which at 5th month are most likely to have approached peak growth.

Figure 2. Effect of age on carcass traits percentage of local chicken.

Differences were also observed for breast percent between rearing system and slaughter age. Semi intensively reared birds had significant higher breast percent (24.9) compared to intensively reared birds (23.6%).  This observation is similar to that reported by Cheng et al (2008) and Castellini et al (2002) who found that breast meat content of carcass increased when birds had access to outdoor production system. This can be explained that the lower stocking density and increased physical activity could reduce the abdominal fat and increase the percentage of breast meat (Lewis et al 1997). But, the findings are contrary to those of Wattanachatt (2008) who reported high percentage of breast muscle from village chickens reared under full feed supplements compared to those under extensive system. Likewise, older birds at 7 month had higher value for breast compared to those at 5 month. Similarly Baéza et al (2012) reported higher meat yield of breast in broiler chicken slaughtered at different ages.


Table 2. Mean values for carcass traits performance of local chicken reared under intensive and semi-intensive systems


Rearing system










Dressing %









Breast %









Thigh %









Drumstick %









SEM = Standard error of mean, P-value = Probability value


Percent drumstick was only influenced by sex and age at slaughter, with higher values in males compared to females and lower value at 7 month (14.5%) compared to a value of 16.2% at five month. These observations imply that slaughter age is most critical in determining dressing percent and weights of carcass components.  The only component that was not affected by slaughter age was the proportion of the thigh. Thus, in deciding as to when birds are to be slaughtered a compromise must be reached taking into account the management system to be adopted. 



The authors would like to thank the Ministry of Livestock and Fisheries Development for the financial support. Appreciation is extended to laboratory technicians and assistant poultry attendants of the department of Animal Science and Production at Sokoine University of Agriculture, for their support in data collection.


Baéza E, Arnould C, Jlali M., Chartrin P, Gigaud V, Mercerand F, Durand C,  Méteau K,  Le Bihan-Duval E and Berri C 2012 Influence of increasing slaughter age of chickens on meat quality, welfare, and technical and economic results. Journal of Animal Science 90:2003-2013. Retrieved on March 27, 2014 from

Castellini C, Mugnai C and Bosco A D 2002 Effect of organic production system on broiler carcass and meat quality. Meat Science, 60:219-225.

Cheng F Y, Huang C W, Wan T C, Liu Y T, Lin L C and Lou Chyr  C Y 2008 Effects of Free-range Farming on Carcass and Meat Qualities of Black-feathered Taiwan Native Chicken Asian-Australian Journal of Animal Science. 21 (8): 1201 – 1206.

Dou T C, Shi S R, Sun J and Wang K H 2009 Growth rate, carcass traits and meat quality of slow-growing chicken grown according to three raising systems. Animal Science Papers and Reports, 27 (4): 361-369.

Fanatico A C, Pillai P B, Cavitt L C, Owens C M, Emmert J L, 2005b Evaluation of slow-growing broiler genotypes grown with and without outdoor access: Growth performance and carcass yield. Poultry Science, 84, 1321-1327.

Goromela E H, Kwakkel R P, Verstegen M W A and Katule A 2006 Strategies to optimize the use of scavengeable feed resource base by smallholder poultry farmers. African Journal of Agricultural Research, 1: 91-100. 

Hassen H, Neser F W C, de Kock A and Van Marle-Köster E 2006 Growth performance of indigenous chickens under intensive management conditions in Northwest Ethiopia. South African Journal of Animal Science 36(5): 71 – 73.

Kitalyi A J 1998: Village chicken production systems in Rural Africa, Household food security and gender issues. FAO, Animal Production and Health Paper, Rome, No 142.

Lewis P D, Perry G C, Farmer L J and Patterson R L S 1997 Responses of two genotypes of chicken to the diets and stocking densities typical of UK and label rouge production systems. I. Performance, Behaviour and carcass composition. Journal of Meat Science. 45:501-516.

Lwelamira J, Kifaro G C and Gwakisa P S 2008 On-station and on-farm evaluation of two Tanzania chicken ecotypes for body weights at different ages and for egg production. African Journal of Agricultural Research 3(12):  843-851. 

Magala H, Kugonza D R, Kwizera H and Kyarisiima C C 2012 Influence of Management System on Growth and Carcass Characteristics of Ugandan Local Chickens. Journal of Animal Science Advance Vol. 2(6): 557-567.

Moreki J C, Dikeme R and Poroga B 2010 The role of village poultry in food security and HIV/AIDS mitigation in Chobe District of Botswana. Livestock Research for Rural Development. Volume 22, Article #5,

Mlozi M R S, Kakengi  A VM, Minga U M, Mtambo A M and Olsen J E 2003 Marketing of free range local chickens in Morogoro and Kilosa urban markets, Tanzania. Livestock Research for Rural Development 15(2).

MLFD 2012: Ministry of Livestock and Fisheries Development. Livestock and Dairy Industry Development in Tanzania. Department of Livestock production and Marketing Infrastructure Development.

Msoffe P L M, Mtambo M M A, Minga U M, Gwakisa P S, Mdegela R H and Olsen J E 2002 Productivity and Natural Disease Resistance Potential of Free-ranging Local Chicken Ecotypes in Tanzania. Livestock Research for Rural Development 14 (3).

Mutayoba S K, Katule A K, Minga U M, Mtambo M M and Olsen J E 2012 The effect of supplementation on the performance of free range local chickens in Tanzania. Livestock Research for Rural Development 24 (5).

Mwalusanya N A, Katule A M, Mutayoba S K, Minga U M, Mtambo M A, Olsen, J E 2002 Nutrient status of crop contents of rural scavenging local chickens in Tanzania. British Poultry Science 43(1):64-9.

Mwalusanya N A, Katule A M, Mutayoba S K, Mtambo M M A, Olsen J E and Minga U M 2001 Productivity of local chickens under village management conditions. Tropical Animal Health and Production, 34: 405-416.

Perry B D, Randolf T F, McDermott J J and Thornton P K 2002 Investing in animal health research to alleviate poverty. ILRI, Nairobi, Kenya, pp: 148.

Raach-Moujahed A and Haddad B 2013 Performance, Livability, Carcass Yield and Meat Quality of Tunisian Local Poultry and Fast-Growing Genotype (Arbor Acres) Fed Standard Diet and Raised Outdoor Access. Journal of Animal Production Advance Vol. 3(3): 75-85.

Raach-Moujahed A, Haddad B, Moujahed N and Bouallegue M. 2011 Evaluation of Growth Performances and Meat Quality of Tunisian Local Poultry Raised in Outdoor Access. International Journal of Poultry Science 10 (7): 552-559.

Sonaiya E B 1990: The context and development of smallholder rural poultry production in Africa. (Proc. Technical Centre for Agriculture and Rural Co operation (CTA), Smallholder rural poultry production Vol: 1 Results and technical papers 9-13 Oct 1990, Thessalonica Greece pp: 35-52. 

Sonaiya E B, Branckaert  R D S, and Gueye E F 1999 Research and development options for family poultry. First INFPD/ FAO electronic conference on family poultry, 7th December 1998-5th March 1999.

SAS 2006: Statistical Analysis Software. The SAS system for Windows (Release 9.1).SAS Institute, Cary, NC, USA.

Thornton P K, Kruska R L, Henniger N, Kristjanson P M, Atieno F, Odero E N and Ndegwa T 2002 Mapping poverty and Livestock in Developing World. ILRI, Nairobi, Kenya, pp: 124.

Wattanachant S 2008 Factors affecting the quality characteristics of Thai indigenous chicken meat. Journal of Science and Technology, 15 (4): 317-332.

Received 25 May 2014; Accepted 1 June 2014; Published 1 July 2014

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